Parkinson's disease is a progressive disorder that affects a small area of cells (called the substantia Nigra) in the middle part of the brain and which occurs slightly more often in men than women. It is also called Shaking palsy or paralysis agitans and is a disorder of the central nervous system primarily attacking people between the ages 50 and 69. Approximately one out of every 1,000 people contact the illness. A cause of Parkinson's disease is that the cells which normally produce dopamine, a chemical necessity for transmitting messages in the brain, degenerate and die causing a deficiency of dopamine and perhaps consequentially the symptoms of Parkinson's disease. The common symptoms include tremor, stiffness (or rigidity) of muscles, slowness of movement (bradykinesia) and loss of balance (postural dysfunction). Parkinson's disease is one of the most prevalent neurological conditions--along with epilepsy, stroke and dementia. The natural history of the disease results in a rate of progression from 10-15 years from onset of the disease, to disability, with some variability from patient to patient. Parkinson's itself, moreover, the disability caused by the disease often leads to fatal infections such as aspiration, pneumonia, and urinary tract infections.
Parkinson's disease is usually categorized into three distinct groups. Paralysis agitans usually called Parkinson's disease is the most common form of Parkinsonism, afflicting approximately 75% of the cases and is of unknown origin or cause. The second type of Parkinsonism which is caused by drugs and toxins, which include carbon monoxide, manganese and chemical compound called MPTP (methyl-phenyltetrahydropyridine). The third form of Parkinsonism is called Vascular Parkinsonism which may be caused by multiple small strokes which damage the dopamine-producing brain cells.
Many treatments have been tried since James Parkinson named and described the condition in 1817. Levodopa or L-dopa is the mainstay treatment in the treatment of Parkinson's disease and may result in a slight loss of disability and a slight increase in life expectancy. L-dopa, however, can begin to lose its effectiveness after a few years. Increases in dose may result in serious side effects which include heart palpitations, involuntary movements, confusion and nausea. Moreover, at its optimum, L-dopa treatment does nothing to inhibit the progressive deterioration of the brain's dopamine producing cells. Since no one knows the exact cause of the dying dopamine-producing cells, it is thought that this replacement therapy, replenishing the brain with the precursor of dopamine would have some value. The value is a slight delay on onset of the disease, reduction of some of the symptoms and slight life expectancy improvement. Recently Vitamins C and E have achieved some success in the treatment of Parkinson's disease so it is thought that antioxidants, like Vitamin C and Vitamin E and others, have a role in Parkinsonism.
Recently, a new drug Eldepryl has proven, in preliminary trials, to slow disease progression by approximately one year.
It is thus a primary object of the present invention to disclose a method of treating Parkinsonism or Parkinson's disease categorized into the three distinct groups named above. While not being limited or bound by any particular theory it is thought that phytic acid will operate through and directly affect Parkinsonism through the following mechanisms. Firstly, it is hypothesized that Parkinsonism may result from toxic iron in the brain. Iron, besides being highly toxic in the brain, stimulates production of free radicals. Free radicals, because of their unpaired electrons and instability and propensity to combine with other biological molecules, are thought to be in excess, damaging to healthy tissue and are being implicated in chronic degenerative diseases such as cancer, arthritis and aging. Phytic acid may thus block iron mediated free radical formation. Like Vitamin C and Vitamin E, phytic acid and its hydrolysates are antioxidants. Moreover, one of the hydrolysates formed by the enzymatic hydrolysis of phytic acid chelates iron, therefore, it may remove excess toxic iron from the substantia nigra.
Secondly, blood glucose is essential to provide the brain with most of its energy. Evidence is being accumulated that in the aging brain uptake of blood glucose may be sub-normal. For example, Alzheimer's patients are thought to hyper-metabolize glucose, thereby depriving the brain of an adequate supply of glucose, its main energy source, resulting in impairment. Thus, a compound which would mediate the blood glucose response would have great value in supplying the brain with sufficient amounts of glucose. This is especially true in the aging brain, where uptake of blood glucose is thought to be subnormal. Phytic acid has been observed to mediate the blood glucose response, so it may alleviate the symptom of Parkinsonism by that mechanism.
Thirdly, cerebral arteriosclerosis or hardening of the arteries, and cerebral atherosclerosis or fatty deposits are a normal consequence of aging and combine to make the arteries increasingly narrow and restricted inhibiting the flow of blood, oxygen and glucose to the brain and is long thought to contribute substantially to the organic deterioration of the brain and mind. Blood supplies the brain cells with the oxygen and nutrients required to remain healthy and function normally. Moreover, waste products are inhibited from leaving the brain because of this condition and it is believed that cerebral arteriosclerosis and cerebral atherosclerosis contribute substantially to impaired brain function with increasing age. In the healthy elderly, in excellent mental and physical health, there may be up to 7% decrease in blood and oxygen flow to the brain. Thus, a compound which would inhibit fatty deposits in cerebral arteries from accumulating or enlarge these atherosclerotic narrowings would have great value in restoring blood and oxygen flow to the brain providing the optimum conditions for normal functioning of the brain. Also, the actual brain cell death in the substantia nigra may be caused by calcium overload. InSP3, a hydrolysate of phytic acid, is known to be a second messenger which controls calcium influx in brain cells. Therefore, replenishing a Parkinsonism patient with phytic acid may supply this calcium mediator to block brain cell death due to calcium overload.
Phytic acid, generally accepted as having the structure myo-inositol-hexakis (dihydrogen phosphate), is a major component of plant seeds, constituting 1-3% by weight of many cereals and oil seeds. Most wheat brans contain between 4 and 5% phytic acid. Phytic acid may be prepared in pure form from various plant sources, such as wheat, corn, soybeans, sesame seeds, peanuts, lima beans, barley, oats, wild rice and sunflower seeds. It can be extracted with dilute hydrochloric acid at room temperature, precipitated with various reagents including ferric chloride, bicarbonates, potassium hydroxide, sodium hydroxide, ammonium hydroxide, calcium hydroxide, magnesium hydroxide or alcohol. It is then further purified by conventional chemical techniques.
When one or more of the acidic protons of the phosphate groups in phytic acid are replaced by a counterion, the compound is usually referred to as a phytate salt. The special name phytin is used for the calcium-magnesium salt of phytate derived from plant seeds (a product of Ciba-Geigy). The present invention includes the use not only of phytic acid and phytate salts, but also various isomeric forms of phytic acid and phytate salts. While the Anderson structure for myo-inositol hexakis dihydrogen phosphate is the accepted structure for phytic acid, the present invention cover other isomers which have been previously described in the literature. These isomers include the cis, epi, allo, muco, neo, D-chiro, L-chiro, and scyllo configurations.
Also, while phytic acid contains six phosphate groups, when introduced into the digestive tract of an animal, one or more of the phosphate groups may be hydrolyzed by the action of the digestive acids and enzymes. Therefore, the present invention includes the use of hydrolysates of phytic acid and phytate salts wherein one or more of the phosphate groups have been removed.
The main uses of phytic acid include use as a food additive for preservation of foods. Studies on the use of phytic acid as a food additive show that ingestion of large doses of phytic acid elicits no physiological discomfort or symptoms of any toxicological action in humans. See Starkenstein, Biochem. Z. 30:56 (1911). Phytic acid and its metabolites are thus not believed to be toxic or highly reactive.
Medical applications of phytic acid include use as an imaging agent for organ scintography, an X-ray enhancement contrasting agent and use to reduce gastric secretion for treatment of gastritis, gastroduodenitis, gastric duodenal ulcers and diarrhea. It has been suggested as an antidote for toxic metal absorption, for therapeutic use in the prevention and dilution of calcium deposits associated with various diseases and for reducing calcium concentration in urine (thus checking the formation of renal calculi). Other uses include as a preventive agent against severe poisoning with pressurized oxygen and preventing thirst during exercise. It has been used as a counterion in salts with various orally administered antibiotics to improve taste.
Phytic acid has also been suggested to reduce the incidence of dental caries, and has been utilized in dentifrices, mouth rinses, dental cements, cleaning agents for dentures and for removing nicotine tar from teeth.
Industrial uses of phytic acid include use as a corrosion inhibitor on metals, a rust remover and an additive to lubricating greases. Other miscellaneous uses of phytic acid include oral administration to treat acne, to improve skin color, blood circulation and fingernail growth; and as an additive in cosmetics for anti-dandruff hair lotions and skin care lotions. One potential agricultural use of phytic acid is to inhibit aflatoxin production by Aspergillus parasiticus. It is also useful as an additive to a fermentation medium containing Micromonospora sagamiensis in the fermentative production of antibiotics. Similarly, phytic acid may be used as a growth-promoting factor in the fermentation medium for the cultivation of yeast for feed.
For further discussions of industrial applications of phytic acid, see Graf, JAOCS 60, 1861-1867 (1983).
Although the above description indicates the broad scope of potential uses of phytic acid, there is not believed to be any suggestion in the prior art that phytic acid is useful for the treatment of Parkinson's Disease.
Accordingly, it is an object of the present invention to provide a method for treatment of Parkinson's Disease by use of phytic acid, phytate salts, and isomers or hydrolysates thereof.
This and other objects will be made apparent by the following description of the preferred embodiments and appended claims.